We employ a developmental perspective to understand the conditions under which state health education curriculum requirements regarding alcohol, tobacco, and other drugs (ATOD) have protective or harmful effects on youth substance use. Multiple youth surveys show that rates of participation in risky behaviors such as consumption of ATOD remain troublingly high in the US despite two decades of modest improvement, suggesting wide latitude for public policy interventions to reduce youth substance use and its related harms. We will create and maintain an ongoing, comprehensive database of state requirements pertaining to ATOD education as well as a variety of other policies pertaining to health education and academic content adopted over the 1990s and 2000s. Developmental theory will guide our empirical models. This theory suggests that the effects of policies will likely vary with the biological age and personal characteristics (e.g., gender, self-control) of students; characteristics of the student's school and peer groups (e.g., prevalence of substance use; peer use); and characteristics of the programs themselves (e.g. duration, approach). We will test these theories with the first comprehensive quasi-experimental analysis of state requirements for ATOD education in health curricula by exploiting substantial variation across states in the timing and implementation of these policies. Our outcome data will include teacher reports of actual health education instruction and youth self-reports of substance use from several representative datasets. This research will significantly advance our understanding of the appropriateness of statewide ATOD curriculum interventions in youth substance use.